Java 中的 LongStream mapToInt()，示例
原文:https://www . geesforgeks . org/longstream-maptoint-Java-examples/
LongStream mapToInt() 返回一个 IntStream，它由给定函数应用于该流元素的结果组成。
注意: LongStream mapToInt()是一个的中间操作。 这些操作总是偷懒。中间操作在流实例上被调用，在它们完成处理后，它们给出一个流实例作为输出。 语法:**
LongStream mapToInt(LongToIntFunction mapper)
参数:
- LongStream : 原始长值元素的序列。这是溪流漫长的原始特化。
- 映射器:应用于每个元素的无状态函数。
返回值:该函数返回一个 IntStream，该 int stream 由给定函数应用于该流元素的结果组成。
例 1 :
// Java code for LongStream mapToInt
// (LongToIntFunction mapper)
import java.util.*;
import java.util.stream.IntStream;
import java.util.stream.LongStream;
class GFG {
// Driver code
public static void main(String[] args)
{
// Creating a LongStream
LongStream stream = LongStream.of(2L, 4L, 6L, 8L, 10L);
// Using LongStream mapToInt(LongToIntFunction mapper)
// to return an IntStream consisting of the
// results of applying the given function to
// the elements of this stream.
IntStream stream1 = stream.mapToInt(num -> (int) num);
// Displaying the elements in stream1
stream1.forEach(System.out::println);
}
}
输出:
2
4
6
8
10
例 2 :
// Java code for LongStream mapToInt
// (LongToIntFunction mapper)
import java.util.*;
import java.util.stream.IntStream;
import java.util.stream.LongStream;
class GFG {
// Driver code
public static void main(String[] args)
{
// Creating a LongStream
LongStream stream = LongStream.of(1L, 2L, 3L, 4L, 5L);
// Using LongStream mapToInt(LongToIntFunction mapper)
// to return an IntStream consisting of the
// results of applying the given function to
// the elements of this stream.
IntStream stream1 = stream.mapToInt(num ->
(int) num + Integer.MAX_VALUE);
// Displaying the elements in stream1
stream1.forEach(System.out::println);
}
}
输出:
-2147483648
-2147483647
-2147483646
-2147483645
-2147483644
例 3 :
// Java code for LongStream mapToInt
// (LongToIntFunction mapper)
import java.util.*;
import java.util.stream.IntStream;
import java.util.stream.LongStream;
class GFG {
// Driver code
public static void main(String[] args)
{
// Creating a LongStream
LongStream stream = LongStream.range(2L, 7L);
// Using LongStream mapToInt(LongToIntFunction mapper)
// to return an IntStream consisting of the
// results of applying the given function to
// the elements of this stream.
IntStream stream1 = stream.mapToInt(num ->
(int) num - 2);
// Displaying the elements in stream1
stream1.forEach(System.out::println);
}
}
输出:
0
1
2
3
4
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